<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<!--vue3 cdn-->
<script src="https://unpkg.com/vue@next"></script>
<div id="counter">
    Counter: {{count}}
</div>
<script>
    const Counter = {
        data() {
            return {
                count: 0
            }
        },
        mounted(){
            setInterval(()=>{this.count++}, 1000)
        }
    }

    Vue.createApp(Counter).mount('#counter');
</script>
</body>
</html>